The invention relates to a process for etching layers which are deposited on transparent substrates such as glass substrates, and more particularly layers with at least moderate electrical conductivity with a view to obtaining electrodes or conducting elements.
The invention deals in particular with layers based on doped metal oxide or based on metal, and preferably those which by virtue of their inherent characteristics and their thicknesses, are transparent. It does not, however, exclude opaque layers.
Many products based on glass substrates do indeed need conducting elements with particular patterns, having good or very high resolution. That is, for example, the case of the electrodes of the glass of emissive screens of the flat screen type, the electrodes of photovoltaic cells or the networks of conducting elements in heated windows or windows incorporating antennas.
U.S. Pat. No. 3 837 944 discloses a technique for chemically etching conducting metal oxide layers, consisting firstly in depositing, on the layer to be etched, a continuous layer based on a resin referred to as xe2x80x9cphotoresistxe2x80x9d which needs to be exposed through a frame, developed then rinsed so as to obtain a mask having the desired pattern. Chemical attack is then carried out on the regions of the layer which are not covered by the resin.
It can be seen that, using this technique, obtaining the mask is complicated and needs a considerable number of steps. It is furthermore unsuitable for small runs, because a new frame needs to be created for each pattern, and unsuitable for substrates with large dimensions.
The object of the invention is therefore to overcome these drawbacks, in particular by providing a novel type of chemical etching which has better performance, an in particular is more flexible to implement, simpler and faster.
The invention relates to a process for chemically etching a layer having electrical conduction properties, of the doped metal oxide type, on a transparent substrate of the glass type, and which includes at least one step of depositing a mask comprising at least one hot-melt ink on the layer to be etched (the term xe2x80x9chot-meltxe2x80x9d ink includes all the inks comprising thermoplastics polymers/materials).